feat(raycast): scaffold Gittensory Raycast extension

[JSONbored]

Parent roadmap: #82

Background

A Raycast extension would give miners and maintainers a fast local command surface for Gittensory without replacing MCP or the GitHub App.

Goal

Scaffold a Raycast extension package that authenticates through GitHub Device Flow and calls the Gittensory API.

Current Behavior

There is no Raycast extension yet.

Desired Behavior

A developer can install/run the extension locally and authenticate with a Gittensory session token, not a GitHub PAT.

Implementation Requirements

• Add package scaffold in a repo-appropriate location.
• Configure TypeScript, lint/test scripts, and Raycast metadata.
• Implement login/status/logout helpers using Gittensory auth.
• Store only Gittensory session token locally.
• Use configurable API origin.

Public/Private Output Boundaries

Raycast is a client surface over the existing Gittensory API/MCP concepts. It must not store GitHub PATs, upload source contents, or expose private scoreability in public GitHub output.

Acceptance Criteria

• Extension builds locally.
• Auth helpers work with mocked API.
• No PAT storage.
• No source upload.
• Package boundaries are documented.

Testing Requirements

• npm run test:ci must pass.
• Global coverage must remain at or above 97% for lines, statements, functions, and branches.
• Aim for 98%+ branch coverage locally to avoid CI variance.
• Add tests for every new branch, fallback path, sanitizer rule, and regression.
• Add invariant/property-style tests when behavior depends on sorting, gating, scoring, queue pressure, source-upload safety, public/private boundaries, or upstream drift.
• Public GitHub output must be tested against forbidden language: wallet, hotkey, raw trust score, payout, reward estimate, farming, private reviewability, and public score estimate.
• MCP/local tooling must prove source contents are not uploaded.

Additional Test Scenarios

• Auth success mock.
• Auth failure mock.
• Session expiry mock.
• No token leakage test.
• Build/lint/test gate.